Although Huntsman didn't mention Perry by name, the tweet was sent within hours of a campaign stop by Perry in New Hampshire where he was asked by the crowd about both topics.

While Perry dodged a question about climate change, he has previously said the theory is unproven. On Thursday, he defended the teaching of creationism in schools because evolution "has some gaps to it."

Perry spokesman Mark Miner said Huntsman, a former governor of Utah, was "entitled to his opinion" but that the Texas governor believes it's important for students to get all pertinent information.

Twitter statistics showed that Huntsman's comment was re-tweeted hundreds of times within a few hours. By comparison, a follow-up tweet by Huntsman criticizing President Barack Obama for taking a vacation received about 50 re-tweets.

Spokesman Tim Miller said Huntsman gained nearly 4,000 new followers in the hours following the tweet, up to more than 16,000.

The tweet reinforced Huntsman's position as the moderate candidate in a race where others are pushing hard to the right.

For a couple of weeks, Huntsman and his staffers have been promising a more aggressive campaign after having pledged to run a civil campaign. Most of their attacks have focused on the front-runner, former Massachusetts Gov. Mitt Romney, and Huntsman has generally been complimentary of Perry.